Transmitter for step-by-step telegraph systems



Sept. 24, 1940. A. E, THoMPsor -.-r m.-

TRANSMITTER FOR STEP-BY-STEP TELEGRAPH SYSTEMS Filed Dec. 29. 1927 4 Sheets-Sheet 1 Fig. 3.

ATTORNEY A 1940' A. E. THOMPSON ET AL 2,215,802

TRANSMITTER FOR STEP-BY-STEP TELEGRAPHSYSTENS,

Filed Dec. 29, 1937 4 Sheets-Shoat 2 Fig. 2. 33 c 33 33 I //V l/f TORY A5 TWOMPSON Y lA-SMMo/y ATTORN Sept 24' 1940 A. E. TH M soN ET AL 2,215,802

TRANSMITTER FOR- STEP-BY-STEP TELEGRAPH SYSTEMS Filed Dec. 29, 1937 4 Sheets-Sheet s Sept. 24, 1940. A. E. THOMPSON arr/u. 2,215,302

TRANSMITTER FOR STEP-BY-STEP TELEGRAPH SYSTEMS Filed Dec. 29, 1937 4 Shets-Sheet 4 Fig, ,10.

//V viii/TORSI- ll. E THOMPJO/Y 610. I/MNO/V Patented Sept. 24, 1940 UNITED STATES TRANSMITTER FOR STEP-BY-STEP TELEGRAPH SYSTEMS Alfred Edward Thompson and Reginald Dennis Salmon, Croydon, England, assignors to Creed and Company Limited, Groydon, Surrey, England Application December 29, 1937, Serial No. 182,201

In Great Britain January 12, 1937 9 Claims. (01. 17s v9) This invention relatesto transmitters for stepby-step type printing telegraph apparatus, and has for its object to provide such a transmitter that will be cheap to construct, that" requires 5 for signalling purposes two line conditions only,

and that can be operated by an unskilled person.

According to one feature of this invention we provide a step-by-step transmitter in which l transmitting contacts are operated by means of a shaft that sends only two or four impulses per revolution of the shaft.

This enables a keyboard to be used for controlling the transmission of the signals, having 15 the keys arranged in a plurality of rows as in a teleprinter or typewriter. Other features of the invention comprise arrangements for looking a depressed key in depressed position and preventing any other key being depressed until 20 the required number of impulses have been sent; and for preventing the simultaneous depression of two keys. An important feature of the invention is that a delay period occurs between the depression of a key and the commencement of 25 the transmission of impulses since this delay ensures a definite pause between successive series of impulses.

The nature of the invention will be better understood from the following description of one 30 embodiment of the invention taken in conjunction'with the accompanying drawings, in which: Fig. l is a plan view of the apparatus, partly in section and with the keyboard omitted;

Fig. 2 is a side elevation of Fig. 1, looking 35 in the direction of the arrow X, but including the keyboard; i

Fig. 3 is a section on the line Ce-C of Fig. 2; Fig. l is a section on the line A-A of Fig. 1; Fig. 5 is a similar section with certain parts 40 omitted; M

Fig. 6 is a view showing an alter-native mechanism to that of Figs. 4 and 5;

Figs. 7, 8 and 9 show details; Figs. ill, 11 and 12 show the mechanism for 4,5 sending out a continuousseries of impulses of long duration for synchronising purposes.

Referring now to the drawings, the apparatus shown therein is adapted to be driven by means of a manually rotatable handle, but it is to be 50 understood that other driving means, such as an electric motor may be used. The handle I is fixed to a lever 2 clamped around a sleeve 3 fixed to a shaft l. This shaft 4 drives, through the medium of a coiled spring, a shaft 9 which must 55 be kept in continuous rotation whilst the transmitter is operated. The shaft 9 drives the driving portions [2a and it of two toothed clutches, the driven portions of which are normally held stationary. When a key is depressed these clutches are tripped and sleeve 22 and shaft 30 *5 are caused to rotate. Sleeve 22, which is driven at a much higher speed than shaft 30, actuates, by means of cams thereon, the transmitting contacts, whilst shaft 30 rotates until one of a helical series of levers 32 thereon releases the key v that has been depressed, whereupon sleeve 22 and shaft 30 are arrested.

The mechanism will now be described in detail. Upon the shaft 4, driven by means of handle I, or by means of a motor, is fixed a cylindrical drum 1. The shaft 9 is supported in bearings to rotate freely and its axis is in line with the axis of shaft 4. One end of a coiled spring 8 is fastened to the interior of drum 1 and the other end to shaft 9, so that shaft 9 is driven from shaft t by tension applied tothe spring 8. A gear wheel l0 fixed on shaft 9 meshes with gear wheels H and I2. Gear wheel 12 is fixed to the driving portion lila of a toothed clutch. Gear wheel ll is fastened on a stub shaft E3 to which is fastened a gear wheel M which meshes with gear wheel [5 fastened on the driving portion iii of a second toothed clutch. The keys 33 are arranged in three rows as in a teleprinter and are carried by key levers 34 all pivoted on a rod 35, andare held in position by individual springs 63. To each key lever 34 is fixed a pair of parallel plates 36 confining between them a two armed lever 39, Ml, pivoted on the key lever by means of a knuckle joint 31 which permits limited movement only. The levers 39, iii are held in position by springs 38 fixed theretoand to the key levers 34. When a key 33 is depressed the lower edge of one of the plates 36 displaces a lever 64, Fig. 3, pivoted at 40 its lower end. Each lever 64 carries a roller 65, and all the levers 64 are confined between fixed pins 66, the pin at one end only of the row being shown, in such manner that when one key lever 34- is depressed, the plate 36 turns the levers 64 on each side of it so that the rollers 65 are all in contact. Two keys cannot be depressed together because there is not sufficient room for displacement of the levers E4 to permit of this.

When a key lever 3 is depressed the depending arm 46 of the two arm lever attached thereto engages a frame 4! and tilts it anti-clockwise and with it the rod 42. Attached to rod 42 is a bent rod 68, and this in turning, draws by means of spring 59 a lever 59, pivoted at T0 and so moves a frame 43 towards the ends of the key levers 34. The upper end of this frame 43 moves in above the end of the depressed key lever and below the ends of the other key levers and so holds the keyboard locked.

Fixed to the rod 42 is a lever 45 (Figs. 4 and 5) pivoted to which is a latch 46, which engages with the end of a lever 18 under the action of a spring 41. Lever 48 is shaped as shown in Fig. 8, is pivoted in blocks 49, 50 and carries a detent 5| that engages with the driven part 52 of a toothed clutch. The part 52 is urged towards the driving part In of the clutch by a spring 53 and is slidably mounted on a shaft carrying a cam 54. Also fixed to the rod 42 is a lever 68 (Fig. 5) against the end of which rests a lever 6i tending to turn clockwise about its pivot '52 under the influence of a spring 73. When rod 42 is turned by the depression of a key, latch 48 pushes lever 48 against spring II to disengage detent 5! from the clutch part 52. The parts 5i and 52 of the clutch engage, and cam 54 is driven by the clutch. As the cam rotates the latch 46 is disengaged from the lever 48 thus permitting lever 48 to arrest the part 52 after it has completed one revolution. At the same time the movement of lever 68 allows lever 6| to move clockwise in Fig. 5. Cam 54 after a period of rotation clockwise in Figs. 4 and 5 depresses a lever 55 and a turned over portion 62 of lever M can move over a nose 53 on lever 55 and hold it depressed. A lever 14 is provided normally held by a spring I5 against cam 54 to prevent any anti-clockwise rotation of such cam and to provide a. definite stop position therefor.

Lever 55 is, in the stationary position of cam 54, held against that earn, by a spring (not shown) similar to spring I5. A second arm 58 of lever 55 carries a detent 51 which normally holds the driven part I1 of a toothed clutch out of engagement with the driving part I6. On the depression of lever 55 by cam. 54 this detent is raised and the clutch engages. A gear wheel 28 and cams 22, 23, and 15 are thereupon rotated.

Cams 22 and 23 act on levers 24 and 25 which carry contacts co-operating with fixed contacts 26, 21 to send reversals to line. Cam I6 00- operates with a lever 11 which holds the cam .shaft in definite position when the clutch parts I6, and I! are disengaged. The speed of the shaft carrying cams 22, 23 and I6 is controlled by a speed governor (not shown).

Gear wheel 25 meshes with gear wheel ill on a stub shaft on which is fixed gear wheel 28. The latter meshes with and thus drives a gear wheel 29 on a shaft 38. The lattercarries a helical series of projections 32, one for each key lever and an indicating wheel 3!. The shaft 30' is driven at such speed that it turns through the distance between two adjacent characters on the wheel 3| for each reversal sent by the cams 22 and 25.

When the projection 32 corresponding to the depressed key lever engages the arm 39 of the lever pivoted thereto, the latter turns on its pivot and the depending arm 48 is disengaged from the frame 4!. The latter is allowed to rise and the consequent turning of rod 42 reengages latch 45 with the nose of lever 48. At the same time lever 69 raises lever SI so as to disengage the portion 62 thereof from the lever 55 and allow it to rise. The rise of lever 55 moves lever 56 to bring the detent 57 into re-engagement with the driven part I! of the other clutch and this part is withdrawn. from engagement with the driving part I6. The machine is thus brought to rest. The turning of rod 42 turns lever 68 and a bent rod I8 which engages therewith is moved to turn rod I8. The lever 43 is thus moved from engagement with the key levers and the depressed key rises under the influence of its spring 63.

It will be observed that there is a definite delay period imposed by the mechanism between the depression of a key and the release for rotation of cams 22 and 23. This ensures, that, if one key is depressed immediately another is released, the two series of impulses do not run into one another, but there is a definite pause therebetween. This is accomplished by the arrangement that the depression of a key first releases a shaft carrying a cam 54 and this cam then releases the transmitting cam shaft.

Ain alternative mechanism for holding the lever 55 depressed after it has been once actuated by the cam 54 is shown in Fig. 6. In this case a lever i9 is fixed to rod 52, and pivoted to latch 19 is a lever 88 with a hooked end shaped as shown in Fig. 6. When rod 42 is turned clockwise in Fig. 6 on depression of a key the hooked end of lever 85 rides on a roller BI mounted adjustably on a bell crank lever 82 pivoted at 83. When lever 55 is depressed by cam 54 latch moves into the path of the end of lever 55. Thus when lever 55 is depressed by cam 54, it is held by latch 80. When the rod 42 is released so as to rotate in a counterclockwise direction the hooked end of latch 85 rises thus allowing lever 55 to rise simultaneously. At the same time the latch 88 engaging with the roller GE is moved back out of the path of the end of lever 55. Thus the depression of a key does not immediately operate lever 55 but lever 55 is held operated until the key is released.

An indicator is provided to show the operator the tension applied to the spring 8 to Warn him when it is too low, and to prevent the tension of spring 8 being increased beyond the limit. For this purpose a gear wheel 6 is provided on shaft 4 and a gear wheel 85 on shaft I. Gear wheel 85 drives, through an idler gear 86, a gear wheel 87 fixed on a sleeve 88 freely turning on a shaft 9|. Gear wheel 5 meshes with a gear wheel 89 on a sleeve 90 also freely rotating on shaft 9|. Carried on sleeves 98 and 88 respectively are gear wheels 92 and 53 which mesh with pinions 94 and 95 carried by a disc 96 secured to shaft 9i. This forms a differential gear and rotates shaft 9| at the diiference of the speeds of gear wheels 6 and 85. Fixed to shaft 9| is a gear wheel 91 which, through gears 98, 99 and I00 drives a sleeve IOI freely rotatable on the shaft. Sleeve IUI carries a cam I52 which acts on levers I83 and I84 (Fig. 9). Lever E33 closes contacts I85 to light a warning lamp when cam I 02 has rotated so far in one direction as to indicate that the tension of spring 8 is too low. When cam I52 has rotated so far in the opposite direction that the tension of spring 8 is too great, lever I 04 is moved by cam 552 into engagement with a cam 5 on the sleeve 3 and tends to hold the handle against being turned thus placing an extra load on the operator.

If a motor be used to drive the apparatus a friction clutch may be placed between the motor shaft and shaft 4 and the lever I04 acting on cam 5 will then hold shaft 4 stationary until the tension of spring 8 has fallen. Alternately the -33 and the subsequent stoppage of the apparatus in a definite position. The key lever I06 has pivoted thereto alever 39a, 40a similar to the lever 38, ill pivoted to other key levers, but there is no projection 32 on the shaft 30 corresponding thereto. The depending arm 40a is very slightly longer than the depending arm 40 of the levers pivoted to other key levers. Key lever idii carries a plate I01 which projects over an adjacent character key lever, say for letter T, and thus when the synchronising key is depressed the adjacent key lever is-also depressed. The frame 41, however, is tilted only by the arm 40a so that when a projection 32 engages the arm 39 of the lever on the key lever for letter T, it has no effect in releasing the keyboard or in stopping the mechanism.

The shaft 3|] carries a gear wheel H2 and mounted to be freely rotatable on a shaft parallel to shaft 30 is a gear wheel III], which is formed with a gap III in its teeth. This gap is normally opposite wheel II 2. Key lever IE6 is extended beyond its pivot 35 and pivoted thereto is a horizontal latch H3 engaging with a bell crank lever H4 pivoted at H5. An arm of the bell crank lever H4 engages a detent I" on wheel IIIJ. Fixed to wheel H3 is an arm I09. When key lever I03 is depressed, latch H3 is removed from lever H4 which is pulled by spring H6 out of engagement with detent H1. Spring H3 one end of which is attached to arm I09 pulls this arm and so rotates wheel H until its teeth mesh with those of wheel H2. Wheel I I0 is then rotated, arm I09 being carried round with it and spring H8 tensioned. This rotation continues until the gap III comes nearly into the position shown in Fig. 12. As soon as the gear teeth come out of engagement spring H8 pulls arm I09 to rotate wheel H0 suddenly into the position shown in Fig. 12. In this last part of the movement arm I09 gives a sudden blow to a bell crank lever I I9 and turns it into contact with the arm 39a of the lever pivoted to key lever I36 and so moves the depending arm iila from engagement with the frame II. The frame 4! rises until it engages with the depending arm 43 ofthe lever pivoted to the key lever for letter T. The control of the transmitter is now with the latter and when the shaft 3|] reaches the position corresponding to letter T,

the key lever for this letter is allowed to rise and the mechanism is restored to normal.

A step by step receiver which is adjusted into a definite position by the receipt of aseries of impulses exceeding a given number, independently of the exact number of impulses is described in our co-pending application Ser. No. 182,200, filed Dec. 29, 1937, and the transmitter described in the present application is intended to co-operate therewith What is claimed is:

1. A step-by-step telegraph transmitter, com prising a transmitting shaft, means for driving said shaft at a predetermined speed, transmitting contacts, means on said shaft to operate said contacts to transmit an even integral number of impulses not greater than four impulses per revolution, a second shaft driven at a speed lower than said transmitting shaft, a plurality of helically arranged projections on said second shaft, transmitter keys representing the characters to be transmitted, members respectively controlled by individual ones of said keys arranged to coact with a respective one of said projections to stop rotation of said shafts and determine the number of impulses transmitted and means controlled by depression of any key for releasing said shafts for rotation.

2. A transmitter according to claim 1 in which said second shaft is driven from said transmitting shaft through reduction gearing.

3. A transmitter for step-by-step telegraphy comprising a rotatable shaft, a plurality of transmitting keys, means actuated by depression of any of said keys for rotating said shaft into a position dependent upon the particular key depressed, a transmitting shaft geared to said first mentioned shaft, transmitting contacts controlled by said transmitting shaft, an intermediate shaft, and meansv operated after a predetermined period of rotation of said intermediate shaft for initiating operation of said transmitting shaft.

4. A transmitter according to claim 3, further comprising means for pivoting said keys on axes parallel to said first mentioned. shaft, means mounted on pivoted levers for preventing simultaneous operation of two keys.

-5. A transmitter according to claim 3, further comprising a plurality of levers for carrying said keys, and means for pivotally supporting said keys in a plurality of parallel rows.

6. A step-by-step telegraph transmitter comprising a transmitting shaft, means for driving said shaft at a predetermined speed, transmitting contacts, means on said shaft for operating said contacts upon rotation of said shaft, a second shaft geared to said transmitting shaft for operation at a lower speed, transmitting keys representing the various characters to be transmitted, means for releasing said transmitting and second shafts for a predetermined period of rotation, upon depression of any key, and means for delaying initiation of rotation of said transmitting shaft and said second shaft for a predetermined period.

7. A step-by-step transmitter comprising a rotatable shaft, a plurality of keys for representing the characters to be transmitted, means actuated by depression of a key for rotating said shaft to a position dependent upon the key depressed, means for transmitting a corresponding number of impulses duringsaid rotation, and means for ensuring a predetermined delay between the depression of a key and the starting of said shaft.

8. A transmitter according to claim 7 in which said last named means comprising an intermedi- 'ate shaft, means actuated by depression of a key for starting said intermediate shaft in rotation, and means actuated by said intermediate shaft after a predetermined period of rotation thereof for starting said first mentioned shaft into rotation.

9. A step-by-step transmitter as claimed in claim 7, further comprising a synchronizing key, means actuated by depression of said synchronizing key for transmitting a plurality of impulses greater than required for any character, and means for bringing the transmitter to rest in a position corresponding to a predetermined character.

ALFRED EDWARD THOMPSON. REGINALD DENNIS SALMON. 

